Aircraft turbine supercharger



May 8, 1945- w. .H. ALLEN AIRCRAFT TURBINE SUPERCHARGER Filed Jan. 7,1942 IhVeTTbOT. Wayne H. AHen,

- His Attorn ey- Patented May 8, 1945 AIRCRAFT TURBINE SUPERCHARGERWayne H. Allen, Los Angeles, Calif., assignor to V General ElectricCompany, a corporation of New York Application January 7, 1942, SerialNo. 425,851

' 4. Claims. (01. 253-39) The present invention relates to aircraftturbine superchargers of the exhaust gas driven type wherein the exhaustgases are discharged from the turbine buckets directly to atmosphere,and especially to such superchargers when arranged on the aircraft withthe axis of the turbine wheel at right angles to the slip stream of theaircraft. With such an arrangement, the slipstream flows transversely ofthe turbine wheel and tends to force gases issuing from the buckets onthe up stream side of the wheel toward the central portion thereof, thuscausing heating of the wheel. Also, after-rburning of the gases issuingfrom the turbine wheel may occur.

One object of the present invention is to provide an improvedconstruction and arrangement for protecting the turbine wheel from thehot exhaust gases which effects a smooth and even tuming of the gasesafter they leave the wheel into the slip stream and which interferes toa minimum with radiation of heat from the turbine buckets.

- the spacing from the disk increasing toward the A further object of myinvention is to provide an improved arrangement for accomplishing theforegoing which-is simple in structure, efiicient in operation, andlight in weight.

For a consideration of what I believe to be novel and my invention,attention is directed to the following specification and the claimsappended thereto.

In the drawing, Fig. l is a front view of a supercharger embodying myinvention; Fig. 2 is a sectional thereof; and Fig. 3 is a detail viewtaken on line 3-3, Fig. 1.

Referring to the drawing, l indicates the shaft of the superchargercarried in a bearing 2 and having overhung on its end a turbine wheelcomprising a central disk 3 on the periphery of which is a ring ofbuckets 4 having at their outer ends a shroud band 5. Gases from theengine or from the source of supply are directed against the buckets bynozzles 8 which form a part of a nozzle box I. to the nozzle-box througha conduit 8. Connected to the nozzle box is a waste conduit 9 in whichis mounted a waste gate valve In for controlling the operation of thesupercharger, as is well understood.

The structure sofar described is to be taken as being typical of anysuitable gas driven turbine The exhaust gases are supplied Y Accordingto my invention, .1 provide a protectingdisk-shaped shield 13 on top ofor on the outboard side of and directly adjacent to the disk 3 of theturbine wheel which is of substantially the same diameter as disk 3, andin connection therewith, I provide a plurality of directing vanes forturning the gases issuing from the turbine wheel buckets through a rightangle and directing them smoothly and evenly into the slip stream. Inthe present instance, I have shown three such vanes,- a vane M at the upstream or what may be termed the top side of the wheel, and two vanes I5at the central portion of the wheel, one being located at each side ofthe wheel. It is to be understood, however, that I may use more thanthree directing vanes in carrying on my invention.

The shield I3 is illustrated as comprising a cap I6 which isconcave-shaped and has a rim l1 .bent inwardly and closely spaced withrespect to the adjacent surface of the bucket wheel disk,

center of the cap. Extending across the center of the cap and securedthereto is a Wall I8 which defines, with the cap, a conduit l9. Theconduit has an inlet opening 20 facing in the direction of the slipstream an located radially beyond the turbine wheel so that no gasesissuing from the turbine wheel may enter the cooling conduit I9. At itslower end wall I8 is spaced from cap Hi to provide a discharge slot-2lthrough which air from the slip stream may be discharged against the rimof the bucket wheel at its lower or trailing side relative to the slipstream. Shield I3 is' supported, preferably from the nozzle box 1, bytwo brackets 22 and 23. In the present instance, bracket 23 extends wellacross wall I8, being attached thereto by a flange 24. It is hollow and,in 'order to cool it, wall I8 is provided with an opening 25 throughwhich air may enter the space between wall it! an the wall of bracket23. Air is discharged from such space through an opening 26. Thebrackets are attached to the nozzle box by studs 21. The specificconstruction of shield 53 is not a part of my present invention, itforming subject matter of the appli-'- cation ofChester W. Smith, SerialNo. 281,562, filed June 28, 1939 and assigned to-the same assignee asthe present application. It is to be taken as typical of any suitableshield for a turbine wheel.

The up stream or top vane 14 is in the form of a. curved hood which isattached to'the nozzle box by spaced ears 29 and studs 30. At itscentral portion, indicated at 3 I, it is curved downwardly tosubstantially the rim of the turbine provided with a slot 32 throughwhich the upper end of wall It extends. From this central portion, vanel4 tapers outwardly on each side as indicated at 33, finally merginginto curved side I flanges 34 which terminate at a point 35 wellhelowthe wheel and have their lower ends connectedtogether by a back plate 86having a rearwardly extending flange 31 which partially surrounds therim of the turbine wheel outside the nozzles and serves to directoutwardly and downwardly gases issuing from the lower side or trailingportion of the turbine wheel. With this arrangement, it will be seenthat the buckets are substantially covered by the vane II at the top ofthe wheel and are progressively uncovered toward the center of thewheel, being fully uncovthe wheel. It extends downwardly to cover asmall arc of buckets, i. e., the are indicated by the line A. From Fig.1 it will be seen that vanes asvaaoa wheel disk, well covering thebuckets, it being I tendency of the slipstream to interfere with thefree discharge of gases from the bucket wheel. As. pointed out before,withoutsuch exhaust hood the slipstream tends to force the gasesdischarged from the leading or top portion of the wheel towards the sideand trailing portion of the wheel.

thus interfering with the discharge of gases from wheel. This top vaneis curved in section, merging gradually into the portion of the exhausthood that surrounds the bucket wheel and. having a radial widthdecreasing from the top towards opposite sides so that the top potrionof the top vane covers the buckets substantially alon their entirelength whereas the side portions of the top vane cover only the outerends of the l4 and; cover the buckets to only a limited extent so thatas the bucket wheel rotates, buckets are always exposed directly to theatmosphere so that they may radiate heat to the atmosphere.

In operation, the exhaust gases issuing from the buckets are turned bythe vanes 14 and i5 and directed into planes substantially parallel withthe plane of the turbine wheel and into the slip stream. The gasesissuing from the upper portion of the buckets are turned by the vane Itand as they flow downwardly they pass over the outer portions of thevanes IS. The gases issuing from the buckets under vanes l5 are turnedby such vanes and directed into a plane parallel to from the bucketsinto the slip stream, I am enabled to efiect efllcient cooling of thewheel and at the same time protect it effectively from the hot gasesissuing from the buckets. At the same time, I utilize a structure whichis relatively light the gases flowing from vane ll. By this arrangement,the gases issuing from the turbine wheel are stratified, so to speak, i.e., they are divided into separate planes. This serves to prevent thegases issuing from theupper part of the wheel from flowing in toward thelower part of the 4 wheel. At the same time, the gases are directedsmoothly into the-slip stream and are carried away by it." Gases issuingfrom uncovered buckets arepicked up and carried along by the gasesdirected across the wheel by the vanes and by the slip stream. Thisarrangement for turning the gases interferes to a minimum with thedistribution of the slip stream air flow over the turbosuperchargerinstallation and also tendsto reduce the'aerodynamic drag of theturbosuper charger installation.

As pointed out above, since the vanes cover only a part of the buckets,there are always buckets exposed directly to atmosphere so that heat canbe radiated from-them tothe atmosphere. Thus, the vanes interfere to aminimum with radiation of heat from the buckets.

From another viewpoint, the vanes described above form part of anexhaust hood for directing gases discharged from a bucket wheel of anairphere'or. from another viewpoint, to reducethe in weight, importantin aircraft applications, and one which is shaped to reduce to a minimumthe aerodynamic drag,

In accordance with the provisions of the patent statutes, I havedescribed the principle of operation of my invention, together with theapparatus which I now consider to represent the best embodiment thereof,but I desire to have it lustrative and that the invention may be carriedout by other means.

. What I claim as new and desire to secure by ring across the outersurface of the shield, said vanes covering only a portion of the bucketring and leaving a substantial portion of the buckets uncovered topermit direct heat radiation therefrom to atmosphere, one of the vanesextending over an arc of about 180 degrees, and the other vanesextending overshorter arcs and being secured to theshield.

2. In a supercharger, a turbine wheel comprising a disk and a ring ofbuckets thereon, a shield for protecting said disk, and a top vane and aplurality of side vanes for directing gases discharged from the bucketring, said vanes covering a partial area only of the ring of bucketsleaving a substantial portion of the ring of buckets free to. radiateheat directly to atmosphere,

'for protecting said disk, a vane across the top of the wheel and sidevanes below the first named vane for directing gases discharged fromsaid bucket ring across the face of the shield,- means including theshield for supporting the vanes, the

understood that the apparatus shown is only ilstantially perpendicularto the direction of the aircraft slipstream, a nozzle box for conductinggases to the wheel, and an exhaust hood fordirecting the gasesdischarged from the wheel into the slip-stream and for protecting thecentral portion of the wheel from the heat of the gases, said exhausthood. including a cap concave= shaped towards the wheel and having a rimclose- 1y spaced with the roots or the buckets, a rear wallconcentrically enclosing the rim of the wheel, a top vane forming acontinuation of the rear walland extending over an arc of about 180angular degrees of the wheel, said top vane having a central portionextending radially towards the roots of the respective buckets andportions on opposite sides of the central portion shaped to cover outerportions oi the buckets only, and other vanes circumferentially spacedfrom the top vane and secured between said cap and the rear wall.

' WAYNE H. ALLEN.

